Injection valve

ABSTRACT

An injection valve as a nozzle opening 53 at the end of a cylindrical line 52, this nozzle opening 53 being formed by a central opening 530 and by peripheral openings 531 grouped therearound. As a result thereof, a fuel jet having a highly articulated and therefore very large surface arises during ejection, this promoting the evaporation of the ejected fuel.

The invention is directed to an injection valve for injecting fuel intoan intake line of an internal combustion engine, wherein the valveincludes a valve body that has an annular valve seat at the inside ofthe injection valve that is concentric with a principle axis, has aclosing part that is arranged displaceable along the principle axis,that is pressed against the valve seat by a spring and that is liftedoff from valve seat with an electro magnet. A cylindrical line orconduit bore that penetrates the valve body from inside the valve seatfrom inside to outside and that discharges at the outside into a nozzleopening is also provided. For example, German published application No.34 11 337 discloses such an injection valve. The fuel is therebyconducted via fuel delivery bores to a concentrating bore that has asignificantly larger diameter and volume than the fuel delivery bores.The fuel should thereby emerge from the fuel delivery bores without wallcontact and should subsequently impact onto the wall of theconcentrating bore in order to flow to the end of the concentrating boreover this distributed film-shaped in roughly the shape of a parabola. Afurther concentrating bore following thereupon is executed such that itsdiameter diminishes to form an ejection section. The ejection sectionalso has teeth directed toward the ejection end.

This embodiment is intended to avoid the formation of larger droplets offuel, so that the fuel ejection ensues uniformly.

Further, German published application No. 34 15 905 discloses anapertured nozzle for internal combustion engines. The nozzle bore havinga cylindrical shape is provided with a surface at a distance from itsregion at the intake side, this surface deviating from the cylindricalshape and acting as a disturbance for the fuel jet to be sprayed inorder to thereby achieve a reduction of the combustion noises.

In comparison thereto, the object of the invention is to fashion aninjection valve such that the quantity of ejected fuel evaporates betterand faster.

The inventive solution of this object is achieved by an injection valveof the type first described above which has a closing part that is flat,a line or conduit that is cylindrical and has a constant diameter, and anozzle opening that is formed by a central opening and by peripheralopenings that surround the central opening, expand toward the outside,and are separated from one another by guide tabs. The peripheralopenings and the guide tabs lie in an annular zone that is arrangedbetween the central opening and the end of the line or conduit and thatdescribes an acute angle of inclination of less than 90° with theprinciple axis. It is based on a special design of the nozzle opening onthe basis whereof one succeeds in lending the ejected fuel jet a highlyarticulated and, thus, extremely large surface that promotes theevaporation of the fuel.

Advantage developments of the invention are achieved in an injectionvalve in which the guide tabs occupy at least a 30% of the area of theannular zone. Such injection valve preferably has the nozzle openinglying co-axially with the principle axis. In such injection valve, everyperipheral opening is symmetrical relative to a secondary axis and thesecondary axes of all peripheral openings proceed from the principleaxis and have the same angular spacing from one another. Such angularspacing is of about 120° and there are three such peripheral openings.Another feature of the injection valve is that the end of everyperipheral opening is limited by a semi-circular end wall or piece. Insuch injection valve to, lateral edges lying opposite one anotherproceed between the end wall of every peripheral opening and the centralopening. Such injection valve has the lateral edges proceeding straightand two lateral edges of neighboring peripheral openings intersecting ina point on the circular central opening.

An alternate injection valve has the lateral edges as circular archesand the lateral edges of neighboring peripheral openings reaching thecircular central opening at a distance from one another. In the presentinjection valve, the annular zone with the nozzle opening may be part ofa separate nozzle member that is secured to the valve body. Such nozzlemember may be a pressure diecast part.

The invention shall be set forth in greater detail with reference to theFIGS. Shown are:

FIG. 1 a longitudinal section through a part of an injection valve;

FIG. 2 a partial view of the nozzle member of FIG. 1 in a greatlyenlarged illustration;

FIG. 3 a partial section along the line III--III in FIG. 2;

FIG. 4 a partial section corresponding to FIG. 2 through a secondembodiment of a valve body;

FIG. 5 a partial section along the line V--V in FIG. 4;

FIG. 6 a partial section like FIG. 4 through a further exemplaryembodiment that differs from that of FIG. 4 on the basis of a differentconnection between nozzle member and valve body;

FIG. 7 a schematic view of the enveloping surface of the ejected fuelthat can be achieved with an injection valve of the invention; and

FIG. 8 a section through the fuel jet of FIG. 6 along the lineVIII--VIII.

Apart from the special design of the nozzle aperture set forth withreference to FIGS. 2ff, the injection valve 1 shown in FIG. 1 has aconventional structure. The housing thereof is only partially shown, theinterior 10 thereof being terminated at one end by a valve body 5. Thishas a line or conduit bore 52 concentric to a principal axis H, thisconduit 52 penetrating the valve body from the inside toward the outsideand being surrounded by an annular valve seat 51 at the inside.

A guide pin 2 on which an armature 3 that carries a flat closing part 4at one end is displaceably seated is arranged in the interior 10concentrically with the principal axis H. The armature together with theclosing part 4 are pressed down by a spring 6, so that the closing part4 is seated on the valve seat 51 and, thus, suppresses the emergence offuel from the interior through the conduit 52. For ejecting fuel, thearmature 3 is drawn slightly upward with the assistance of anelectromagnet (not shown) and the valve is thus opened. Without specialmeasures, a compact fuel jet thereby arises having an essentiallycircular cross-section and a relatively small surface.

The invention succeeds in considerably enlarging the surface of the fueljet. To this end, the nozzle opening 53 at the end of the line 52 has aspecial design that may be seen particularly clearly from FIGS. 3 and 5:it is formed of a circular central opening 530, 530' and by threeperipheral openings 531, 531' that outwardly expand the central opening530, 530' and that lie in an annular zone 540, 540' that extends betweenthe central opening 530, 530' and the end of the line 52. The annularzone describes an angle α of inclination with the principal axis H thatis smaller than 90° and preferably lies between 30° and 60°: the jetcone of the ejected fuel is all the larger the smaller this angle.

The peripheral openings 531, 531' are fashioned symmetrically relativeto secondary axes N that have the same angular spacing α of 120° fromone another. Every peripheral opening 531, 531' is limited at its end bya semicircular end piece or wall 5310, 5310' and by lateral edges 5311that lie opposite one another and adjoin thereto. These lateraledges--executed straight according to FIG. 3--of neighboring peripheralopenings respectively intersect in a point on the circular centralopening 530: as a result thereof, roughly triangular guide tabs 5401that reduce the diameter of the overall nozzle opening in comparison tothat of the conduit 52 arise within the annular zone 540 betweenneighboring peripheral openings 531. As a result thereof, a peripheraljet 12 arises per peripheral opening 531 when ejecting the fuel, thisperipheral jet 12 being connected to a central jet 14 via a narrowconnecting section 16, as FIGS. 7 and 8 show. The surface of the overalljet resulting therefrom is obviously significantly larger than that of acompact jet having an essentially circular crosssection.

According to FIGS. 2 and 3, the valve body 5 and the nozzle member 54comprising the nozzle opening 53 are of one piece and are composed ofstainless steel because of the stressing of the valve seat 51. Incontrast thereto, a separate nozzle member 54', 54" is providedaccording to FIGS. 4-6, this being preferably a pressure diecast part(zinc pressure diecasting) and being capable of being manufactured in asimple way with high precision.

In the exemplary of FIGS. 4 and 5, the nozzle opening 53' is againformed by a circular central opening 530' and by three peripheralopenings 531' extending radially outward therefrom, each of theseperipheral openings 531' having a semicircular end piece or wall 5310'at the end. The lateral edges 5311' that, by contrast to the exemplaryembodiments set forth above, represent a circular arc adjoin thereto.The radius of every peripheral opening is smaller than the exemplaryembodiment set forth above, so that larger guide tabs 540' arise betweenthe lateral edges 5311' of neighboring peripheral openings 531'.

The guide tabs preferably occupy at least 30% of the area of the annularzone, whereby the radial width of the annular zone lies between 20% and50% of the radius of the conduit 52, 52'.

When, as in FIGS. 1-3, the valve body 5 and the nozzle member 54 arefashioned of one piece, the shape of this part can be realized withknown fabrication techniques: the valve body can be cast or cold-worked.A combination of these two manufacturing steps is particularlyexpedient, whereby a cast valve body receives its ultimate shape and theexact dimensions with a following cold-working. It is also possible toplastically shape a valve body with a through continuous line with theassistance of a die placed at the nozzle opening, i.e. to press materialfrom the region around the nozzle opening into the nozzle opening. Itmust thereby be taken into consideration that the diameter of the line52 lies on the order of magnitude of only 1 mm; that, thus, FIGS. 2-6show a roughly 40-fold magnification of the real situation.

A high precision can be most simply assured with the separate nozzlemember 54', 54" of a zinc diecast that, according to FIGS. 4 and 5, isconnected to the valve body 5', 5" with a nozzle tube 541' and,according to FIG. 6, is connected thereto with a nozzle flange 542". Inthe former case, a non-positive or material-actuated connection isprovided; in the latter case, a positive connection is provided on thebasis of a beaded edge 50".

Although other modifications and changes may be suggested by thoseskilled in the art, it is the intention of the inventors to embodywithin the patent warranted hereon all changes and modifications asreasonably and properly come within the scope of their contribution tothe art.

I claim:
 1. An injection valve for injecting fuel into an intake line ofan internal-combustion engine, comprising:a valve body that has anannular valve seat at an inside of the injection valve, said valve bodybeing concentric with a principle axis; a closing part mounted fordisplacement along the principle axis, said closing part being flat; aspring mounted to press said closing part against said valve seat; anelectromagnet mounted to lift said closing part of said valve seat; acylindrical conduit that penetrates said valve body inside said valveseat from inside to outside, said conduit being cylindrical and ofconstant diameter; through which said conduit discharges to outside saidvalve body, said nozzle opening being formed by a central opening, andperipheral openings that surround said central opening and expand towardthe outside, guide tabs separating said peripheral openings from oneanother; said peripheral openings and said guide tabs lying in anannular zone that is arranged between said central opening and an end ofsaid conduit and that describes an acute angle of inclination of lessthan 90° with the principle axis.
 2. An injection valve according toclaim 1, wherein said guide tabs occupy at least 30% of an area of saidannular zone.
 3. An injection valve according to claim 2, wherein saidnozzle opening lies coaxially with the principle axis.
 4. An injectionvalve according to claim 3, wherein every one of said peripheralopenings is symmetrical relative to a secondary axis, said secondaryaxes of all of said peripheral openings proceeding from the principleaxis and having the same angular spacing from one another.
 5. Aninjection valve according of claim 4, wherein three of said peripheralopenings are formed in said nozzle opening, and said angular spacingbetween said peripheral openings is substantially equal to 120°.
 6. Aninjection valve according to claim 4 wherein, an end of every one ofsaid peripheral openings is limited by a semicircular end wall.
 7. Aninjection valve according to claim 6, wherein each of said peripheralopenings has two lateral edges lying opposite one another and proceedingbetween said end wall of every one of said peripheral openings and saidcentral opening.
 8. An injection valve according to claim 6, whereineach of said peripheral openings has lateral edges formed as circulararcs; and said lateral edges of neighboring ones of said peripheralopenings reach said central opening at a distance from one another. 9.Injection valve according to claim 8, characterized in that the lateraledges (5311') are circular arcs; and in that the lateral edges (5311')of neighboring peripheral openings (531') reach the circular centralopening (530') at a distance from one another.
 10. An injection valveaccording to claim 1, further comprising:a separate nozzle member thatis secured to said valve body, said separate nozzle member includingsaid annular zone and said nozzle opening.
 11. An injection valveaccording to claim 10, wherein said separate nozzle member is a pressurediecast part.